In this study the geotechnical system response probabilities (SRP) of the failure modes caused by the interal erosion in three dams with different histories of defects in Korea were analyzed via the internal erosion toolbox developed by USACE. The calculated values of SRP were compared with the values reported for other dams in worldwide and also the statistics on the past failures of dams and embankments in Korea. The calculated values of SRP related to the internal erosion adjacent to the conduits or spillway structures are as high as in the order of that is significantly greater than the SRP values related to other mechanisms of internal erosion. The statistical data showing that the interal erosion adjacent to the structure is the most frequent cause of the failure of the dam in Korea could be a collateral evidence of this finding. In contrast, the values of SRP related to the internal erosion through foundation, one of the major causes of dam failure in worldwide, are relatively as low as in the order of . This result could be comparable with the rareness of the failure cases of dam caused by the internal erosion through foundation in Korea.

Foster, M. and Fell, R. (1999). A framework for estimating the probability of failure of embankment dams by internal erosion and piping using event tree methods. UNICIV Report No. R-377, University of New South Wales, Australia.

Wan, C. F. and Fell, R. (2002). Investigation of internal erosion and piping of soils in embankment dams by the slot erosion test and the hole erosion test. UNICIV Report No. R-412, University of New South Wales, Australia.